*/
    map.put(Integer.class, new Integer(5));
    assertThrows(ClassCastException.class, () -> map.put(Double.class, new Long(42)));
    // Won't compile: map.put(String.class, "x");
  }

  public void testPutAndGetInstance() {
    assertThat(map.putInstance(Integer.class, new Integer(5))).isNull();

    Integer oldValue = map.putInstance(Integer.class, new Integer(7));
    assertEquals(5, (int) oldValue);